Optical communication device

This application is a US National Stage of International Patent Application PCT/JP2022/033516, filed on Sep. 7, 2022, the contents of which are incorporated herein by reference.

The present disclosure relates to an optical communication device.

In next-generation mobile communication systems in conformity with B5G/6G or the like, broadband wireless communication using small cells is executed. Further, a huge amount of data communication is being required of the next-generation mobile communication systems. In such a circumstance, All Photonics Network (APN) has been proposed. The APN is described in Non-patent Reference 1.

A network in which a huge amount of data communication is executed includes Wavelength Division Multiplexing (WDM) optical communication devices. The WDM optical communication device includes a muxponder. The muxponder converts a low-speed client signal based on Ethernet (registered trademark), Synchronous Digital Hierarchy (SDH) or the like to a high-speed signal suitable for WDM communication. The APN includes WDM optical communication devices including muxponders.

A communication range of a base station in B5G/6G is narrow. Therefore, a plurality of base stations is installed. However, when a plurality of base stations has been installed, there appears a base station not executing communication out of the plurality of base stations. For example, when four base stations have been installed in a certain area, the number of base stations communicating with a user is one. Accordingly, three base stations are set in a no-signal state as a state of not executing communication. As above, when a plurality of base stations is installed, there is a fear of an increase in the no-signal state. Thus, it increases situations where the communication bandwidth cannot be effectively used, and the operation of the optical communication device becomes inefficient.

In a Passive Optical Network (PON) system, there are cases where an ONU transmits empty frames including no user data. When the ONU transmits empty frames, the effective use of the communication bandwidth is not achieved. To deal with this problem, there has been proposed a technology in which a device in Patent Reference 1 determines the presence/absence of a data signal contained in a frame and disconnects a logical link determined to be carrying no data signal out of a plurality of logical links (see Patent Reference 1).

Additionally, there exists an optical communication device that transmits a multiplexed signal obtained by multiplexing a plurality of client signals. Further, this optical communication device is a device capable of receiving data traffic corresponding to a predetermined communication bandwidth. For example, this optical communication device is a device capable of receiving data traffic corresponding to a communication bandwidth “100 Gbit/sec”.

Incidentally, there are case where a client signal as an empty frame is transmitted to the optical communication device. In such cases, the communication traffic of the multiplexed signal is lower than the predetermined communication bandwidth. The low communication traffic means that the effective use of the communication bandwidth is not achieved.

An object of the present disclosure is to make the effective use of the communication bandwidth.

An optical communication device according to an aspect of the present disclosure is provided. The optical communication device includes a signal multiplexing unit that multiplexes a plurality of client signals and a signal transmission unit that converts a first multiplexed signal obtained by the multiplexing to an optical signal and transmits the optical signal. The optical communication device is a device capable of receiving data traffic greater than data traffic corresponding to a predetermined communication bandwidth.

According to the present disclosure, the effective use of the communication bandwidth can be achieved.

Embodiments will be described below with reference to the drawings. The following embodiments are just examples and a variety of modifications are possible within the scope of the present disclosure.

is a block diagram showing functions of an optical communication device in a first embodiment. The optical communication deviceincludes a client Interface (I/F) unit, transmission signal processing units_, . . . ,_(m is a positive integer), a monitoring control unit, a signal multiplexing unit, a signal transmission unit, a signal reception unit, a signal splitting unit, and reception signal processing units_, . . . ,_. Further, the optical communication devicemay be implemented by a muxponder.

Here, the optical communication devicewill be described briefly. The optical communication deviceis capable of receiving a plurality of client signals. The optical communication deviceis a device capable of receiving data traffic greater than data traffic corresponding to a predetermined communication bandwidth. For example, the predetermined communication bandwidth is assumed to be 100 Gbit/sec. The communication bandwidth of the client signal is assumed to be 10 Gbit/sec. When the number of client signals is 20, the optical communication devicereceives data traffic corresponding to 200 Gbit/sec. Therefore, when the optical communication devicereceives 20 client signals, the optical communication devicereceives data traffic greater than the data traffic corresponding to the communication bandwidth 100 Gbit/sec. For example, in order to receive great data traffic, the optical communication deviceincludes the same number of transmission signal processing units as the client signals to be received. Incidentally, there are cases where the optical communication devicereceives client signals being empty frames. For example, even when 10 client signals out of the 20 client signals are empty frames, the optical communication deviceis capable of transmitting communication traffic corresponding to the predetermined communication bandwidth. In short, the optical communication deviceis capable of transmitting data at 100 Gbit/sec. Since the optical communication deviceis capable of receiving data traffic greater than the data traffic corresponding to the predetermined communication bandwidth as above, the optical communication deviceis capable of making the effective use of the communication bandwidth even when client signals being empty frames are received.

As described above, there are cases where the optical communication devicereceives data traffic greater than the data traffic corresponding to the predetermined communication bandwidth. Therefore, when the received data traffic exceeds the data traffic corresponding to the communication bandwidth, the optical communication deviceadjusts the communication traffic to the communication bandwidth. Then, data not included in the communication traffic is stored in a buffer. For example, the communication bandwidth is assumed to be 100 Gbit/sec. The optical communication deviceis assumed to receive data traffic corresponding to 150 Gbit/sec. The optical communication devicemultiplexes a plurality of client signals corresponding to the data traffic corresponding to 100 Gbit/sec and transmits the multiplexed signal. Further, the optical communication devicestores data traffic corresponding to 50 Gbit/sec in the buffer. Since the communication traffic is adjusted to the communication bandwidth as above, the optical communication deviceis capable of transmitting data at the communication bandwidth. The following description will be given mainly of such features.

In the following description, the transmission signal processing units_, . . . ,_can be collectively referred to as transmission signal processing units. The reception signal processing units_, . . . ,_can be collectively referred to as reception signal processing units.

Part or all of the client I/F unit, the transmission signal processing units, the monitoring control unit, the signal multiplexing unit, the signal transmission unit, the signal reception unit, the signal splitting unitand the reception signal processing unitsmay be implemented by processing circuitry.

The client I/F unitreceives m client signals each at a communication rate n. Incidentally, the client signals are signals transmitted from a client device. Illustration of the client device is left out. Further, the client I/F unittransmits m client signals to the client device. Here, each client signal is referred to also as a frame.

Next, the transmission signal processing unitwill be described below.

is a block diagram showing functions of the transmission signal processing unit in the first embodiment. The transmission signal processing unitincludes a decoder, a frame analysis unit, a frame processing unitand a buffer.

The decoderdecodes the client signal. For example, the decoderdecodes the client signal encoded according to 8B/10B, 64B/66B or the like.

The frame analysis unitanalyzes data size of the client signal obtained by the decoding.

The frame processing unitstores the client signal in the buffer.

The bufferstores the client signal.

As above, the transmission signal processing units_, . . . ,_store a plurality of client signals received by the optical communication devicein a plurality of buffers. Here, the plurality of buffers may also exist outside the transmission signal processing units_, . . . ,_. Further, the plurality of buffers existing outside may be integrated into one buffer. Thus, it can also be expressed that the transmission signal processing units_, . . . ,_store a plurality of client signals received by the optical communication devicein one or more buffers.

Next, returning to, the monitoring control unitwill be described below.

The monitoring control unitobtains the data traffic (data amount) of the plurality of client signals stored in the one or more buffers. The monitoring control unitjudges whether or not the obtained data traffic exceeds the data traffic corresponding to the predetermined communication bandwidth. For example, the monitoring control unitjudges whether or not the obtained data traffic exceeds the data traffic corresponding to the predetermined communication bandwidth “100 Gbit/sec”. When the obtained data traffic exceeds the data traffic corresponding to the predetermined communication bandwidth, the monitoring control unitissues a command so as to transmit a plurality of client signals corresponding to the data traffic corresponding to the communication bandwidth to the signal multiplexing unit.

Upon receiving the command, the transmission signal processing units_, . . . ,_transmit the plurality of client signals corresponding to the data traffic corresponding to the communication bandwidth stored in the one or more buffers to the signal multiplexing unit. Specifically, the transmission signal processing units_, . . . ,_acquire the plurality of client signals corresponding to the data traffic corresponding to the communication bandwidth from the one or more buffers. For example, the transmission signal processing units_, . . . ,_acquire the plurality of client signals corresponding to the data traffic corresponding to the communication bandwidth “100 Gbit/sec” from the one or more buffers. The method of acquiring the plurality of client signals corresponding to the data traffic can be any kind of method. For example, when there exist 10 buffers, the transmission signal processing units_, . . . ,_acquire the plurality of client signals corresponding to the data traffic corresponding to “10 Gbit/sec” from the 10 buffers.

The signal multiplexing unitmultiplexes the plurality of client signals transmitted from the transmission signal processing units_to_. The multiplexed signal obtained by multiplexing the plurality of client signals is referred to also as a first multiplexed signal.

The signal transmission unitperforms a scramble process, an error correction encoding process and a transmission encoding process on the multiplexed signal. After finishing these processes, the signal transmission unitconverts the multiplexed signal to an optical signal. Here, the optical signal may be referred also to as a line signal. The signal transmission unittransmits the optical signal to an optical transmission line.

The signal reception unitreceives an optical signal from the optical transmission line. The signal reception unitconverts the optical signal to an electric signal. By this, the signal reception unitacquires a multiplexed signal (i.e., an electric signal). The signal reception unitperforms a transmission decoding process, an error correction decoding process, and a descramble process on the multiplexed signal. Here, this multiplexed signal is referred to also as a second multiplexed signal.

The signal splitting unitsplits the multiplexed signal. By this, m electric signals are inputted to the reception signal processing units_to_

Next, the reception signal processing unitwill be described below.

is a block diagram showing functions of the reception signal processing unit in the first embodiment. The reception signal processing unitincludes a frame analysis unit, a frame processing unitand an encoder.

The frame analysis unitanalyzes boundaries of frames included in the inputted electric signal. Here, this electric signal is referred to also as a first electric signal.

The frame processing unitsplits the electric signal based on the boundaries of the frames. Each electric signal obtained by the splitting is referred to also as a frame or a client signal. In the following description, each electric signal obtained by the splitting is referred to as a frame. The frame processing unittransmits the frames to the encoderin consideration of a time represented by a packet gap. In other words, the frame processing unittransmits the frames to the encoderwhile securing spacing of the packet gap. For example, the frame processing unittransmits a first frame to the encoder. The frame processing unitstays on standby for the time represented by the packet gap. The frame processing unittransmits a second frame to the encoder.

The encoderencodes the frames. For example, the encoderperforms encoding according to 8B/10B, 64B/66B or the like on the frames. The encodertransmits the encoded frames to the client I/F unit.

Next, a process executed by the transmission signal processing unitwill be described below by using a concrete example.

is a diagram showing a concrete example of the process executed by the transmission signal processing unit in the first embodiment.will be explained by using an Ethernet. The explanation ofwill be given by using frames. As mentioned earlier, a frame is referred to also as a client signal.

shows a case where an (N−1)-th, an N-th and an (N+1)-th frames are inputted to the transmission signal processing unit. Specifically, after the (N−1)-th frame is inputted to the transmission signal processing unit, the transmission signal processing unitstays on standby for the time represented by the packet gap as an Interframe Gap (IFG). Then, the N-th frame is inputted to the transmission signal processing unit. After the N-th frame is inputted to the transmission signal processing unit, the transmission signal processing unitstays on standby for the time represented by the packet gap. Then, the (N+1)-th frame is inputted to the transmission signal processing unit.

Here, the format of the frame will be described below. The frame includes an OverHead (OH), Data, and a Frame Check Sequence (FCS).

The (N−1)-th, the N-th and the (N+1)-th frames are stored in the buffer.

Next, a process executed by the reception signal processing unitwill be described below by using a concrete example.

is a diagram showing a concrete example of the process executed by the reception signal processing unit in the first embodiment.will be explained by using an Ethernet.

The frame analysis unitanalyzes the boundaries of the frames included in the inputted electric signal. For example, the frame analysis unitdetects a border between an FCS and an OH as the boundary of the frame.

The frame processing unitsplits the electric signal based on the boundaries of the frames. By this, the electric signal is split into an (M−1)-th, an M-th and an (M+1)-th frames.

The frame processing unittransmits the (M−1)-th frame to the encoder. The frame processing unitstays on standby for the time represented by the packet gap as the IFG. The frame processing unittransmits the M-th frame to the encoder. The frame processing unitstays on standby for the time represented by the packet gap. The frame processing unittransmits the (M+1)-th frame to the encoder.

Next, a process executed by the optical communication devicewill be described below by using a flowchart.